At the start of each pool game, the balls are placed in the rack which positions the balls into the proper placement for the start of the game and they are then placed in a proper position on the table. In a normal game of pool, fifteen balls are placed in the rack in a pyramid shape. There are other pool games, however, where only nine balls are used and still other pool and billiard games where various amounts of balls are used.
Referring to the more common game of pool where fifteen balls are used, the 15 balls are placed into the rack, placed in the proper position on the table and then the player must carefully lift the rack vertically upward attempting not to touch the balls or jimmy them in any manner whatsoever so that the balls are not moved out of the proper position.
With the standard solid pool rack, even with the utmost of care, the player can often disturb the balls thus making a loose or out of position rack of balls.